We have now reached one of the most solemn and fear-provoking sections of Scripture. We need to understand that this passage is written to Christians, not to the world, and what it threatens is facing any Christian who does not choose to believe that God is serious. God is thundering at His own children because some of them have become insipidly blasé about what He has done for them and have ignored the help that He makes so readily available to them.
This does not mean that everybody who heard this message was in that perilous spiritual condition. It was given, however, against the backdrop of some having already departed from the church, and it uses them as examples of what not to do, for the purpose of warning the others about what those who left are facing. To determine just where he stands, each person has to examine himself in light of Paul's instruction.
Yet, some who heard this message had regressed so far that they were on track to apostatize, which means "to depart from the faith." This subject is Paul's major motivation for writing the letter. He first introduces it as early as Hebrews 3:12: "Beware, brethren, lest there be in any of you an evil heart of unbelief in departing from the living God." "Departing" is the Greek word aphistemi, meaning "to remove" or "to instigate to revolt."
How far had people departed? Hebrews 10:25 gives a clear indication by Paul's use of the word "forsaking" regarding assembling on the Sabbath. The Greek word means exactly this: Some of the Hebrews were not missing just an occasional Sabbath service but had abandoned attending Sabbath services entirely for extended periods, if not altogether. This accounts for the strength of the apostle's message.
A similar passage in II Peter 2:20-22 reads:
For if, after they have escaped the pollutions of the world through the knowledge of the Lord and Savior Jesus Christ, they are again entangled in them and overcome, the latter end is worse for them than the beginning. For it would have been better for them not to have known the way of righteousness, than having known it, to turn from the holy commandment delivered to them. But it has happened to them according to the true proverb: "A dog returns to his own vomit," and, "a sow, having washed, to her wallowing in the mire."
Peter speaks of apostasy here. He says it would have been better had they never known the way of righteousness rather than know it and then turn from it. Jesus said of Judas that it would have been better for him not to have been born (Matthew 26:24). The same end faced those who had forsaken assembling together on the Sabbath.
I Timothy 1:19 contains a vivid illustration of apostasy, saying that an apostate makes shipwreck of his faith in God. Having escaped the world, he returns to it and soon finds himself on the rocks, being beaten to death by the waves of life. As mentioned earlier, a person does not apostatize in one giant leap. Just as the Israelites obtained the Promised Land step by step, so apostasy occurs step by step. One goes forward, the other backward. If the backslider takes appropriate action, he does not have to lose his faith.